Computing systems have dramatically changed the way in which we live. The first wave of computers was prohibitively expensive, and was only cost effective for use in business settings. As computers became more affordable, the use of personal computers both in the workplace and at home have become so widespread that computers have become as common as desks in the office and kitchen tables in the home. Microprocessors have been incorporated in all aspects of our daily lives, from use in television and other entertainment systems to devices for regulating the operation of our automobile.
The evolution of computing devices, from data crunching devices that occupied entire floors of large office facilities, to laptop computers or other portable computing devices, has dramatically impacted the manner in which documents are generated and information is stored. Portable computing capabilities have enabled individuals to type letters, draft memorandum, take notes, create images, and perform numerous tasks in places other than the office using these computing devices. Professionals and nonprofessionals alike are empowered to perform tasks while on the move using devices that fulfill their computing needs in any location.
Typical computer systems, especially computer systems using graphical user interface (GUI) systems, such as Microsoft® Windows, are optimized for accepting user input from one or more discrete input devices such as a keyboard (for entering text), and a pointing device (such as a mouse) with one or more buttons for activating user selections.
One of the original goals of the computing world was to have a computer on every desk. To a large extent, this goal has been realized by the personal computer becoming ubiquitous in the office workspace. With the advent of laptop computers and high-capacity personal data assistants, the office workspace has been expanded to include a variety of non-traditional venues in which work is accomplished. To an increasing degree, computer users must become masters of the divergent user interfaces for each of their computing devices. From a mouse and keyboard interface for the standard personal computer to the simplified resistive stylus interface of personal data assistants and even to the minimalistic keys of a cellular telephone, a user is confronted with a variety of different user interfaces that one needs to master before he can use the underlying technology.
Despite the advances in technology, most users tend to use documents printed on paper as their primary editing tool. Some advantages of printed paper include its readability and portability. Others include the ability to share annotated paper documents and the ease at which one can archive printed paper. One user interface that is bridging the gap between advanced computing systems and the functionality of printed paper is a stylus-based user interface. One approach for the stylus-based user interface is to use resistive technology (common in today's PDAs). Another approach is to use active sensors in a laptop computer. One of the next goals of the computing world is to bring the user interface for operating the computer back to the user.
A drawback associated with the use of a stylus is that such devices are tied to the computing device containing the sensor board. In other words, the stylus may only be used to generate inputs when used in conjunction with the required sensor board. Moreover, detection of a stylus is affected by the proximity of the stylus to the sensing board.
Prior portable computing devices may lack a specific form of identification for multiple user configurations. As such, if two such portable computing devices operated simultaneously, a host computer becomes confused and senses the annotations to be from the same computing device. If one user annotates a document with the computing device and then a second user annotates the same document with a second computing device, the host PC that receives the data frames from the computing device interprets the data as originating from the same computing device. Without an ability to identify the computing device from which an annotation occurs, a host PC cannot track changes specifically to a particular computing device.
Prior portable computing devices may lack the ability to track writing that a user may perform on top of existing ink. Prior computing devices may track writing of a user on clean, ink free surfaces; however, the image capturing capabilities of these devices cannot track writing that occurs on existing ink. Further, prior portable computing devices may lack the ability to handle perspective that naturally exists when a writing implement, such as a pen, is held. An image sensor of an associated computing device operates efficiently when a user holds the computing device at an angle that is perpendicular to the writing surface. However, most individuals do not hold a pen at a 90 degree angle to a surface. As such, perspective becomes a problem for the sensor to adequately compensate for the angle of the computing device.
There is a need in the art for a portable computing device that may function as an input device for any one of a variety of computing devices and which may operate in a variety of situations. There is a further need in the art for a portable computing device that can be identified by a specific identification in order to allow for multiple users to operate on a document and/or within an application program simultaneously. Also there is a need in the art for a portable computing device that may decrease the effect of perspective in capturing images on a surface and may be configured to track writing by a user on existing ink.